应用二维热阻图研究空心节能墙体砌块传热特性

Two-dimension thermal resistant circuit method for calculating heat transfer through energy saving wall block with cavities

对空心节能墙体砌块,应用二维热阻图改进传统的一维传热估算法求解热阻图中各节点能量方程得出了墙体砌块传热特性。分析墙体黑度ε对传热的影响可知:随ε增大,孔洞中辐射换热作用增强,对流换热减弱,一般材料的墙体砌块辐射换热量和对流换热量与砌块总换热量之比均为35%左右。单排孔砌块的热阻不一定高于无孔砌块的热阻,但两排孔砌块可比无孔砌块节能29%。计算与测试结果的比较表明计算是可靠的。

The practical two-dimension thermal resistant circuit method for researching heat transfer through energy saving wall block with cavities improves common one-dimension heat transfer analysis methodology. Solving nodal energy equations gets heat transfer characteristics of the wall block. The effect of surface emissivity ε on heat transfer was analyzed: radiant heat transfer in cavity increases as ε increases, however convective heat transfer decreases with increase in ε. The ratio of radiant heat transfer to total heat transfer across wall block with one-line cavity made of ordinary building material is about 35% as well as the ratio of convective heat transfer to total heat transfer. Heat resistance value of block with one-line cavity may be less then heat resistance value of block with no cavity. The block with two-lines cavities saves energy 29%. The comparison of calculation in this paper with test results approved the calculation.